CA1052673A - Method for producing an apertured work piece - Google Patents
Method for producing an apertured work pieceInfo
- Publication number
- CA1052673A CA1052673A CA231,291A CA231291A CA1052673A CA 1052673 A CA1052673 A CA 1052673A CA 231291 A CA231291 A CA 231291A CA 1052673 A CA1052673 A CA 1052673A
- Authority
- CA
- Canada
- Prior art keywords
- smaller
- mils
- etch
- open areas
- sheet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/14—Manufacture of electrodes or electrode systems of non-emitting electrodes
- H01J9/142—Manufacture of electrodes or electrode systems of non-emitting electrodes of shadow-masks for colour television tubes
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/02—Local etching
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- ing And Chemical Polishing (AREA)
Abstract
METHOD FOR PRODUCING AN APERTURED WORK PIECE
ABSTRACT OF THE DISCLOSURE
An apertured work piece, such as a shadow mask for a color television picture tube, is produced by coating opposite major surfaces of a thin metal sheet with etch-resistant patterns. One pattern comprises an array of larger open areas surrounded by etch-resistant material, and the other pattern comprises smaller open areas of similar shape and registered with the larger open areas.
Each of the smaller open areas has therewithin a still-smaller solid area of etch-resistant material. The coated sheet is etched from both sides to produce the desired apertures, and then the coatings are removed from the sheet.
ABSTRACT OF THE DISCLOSURE
An apertured work piece, such as a shadow mask for a color television picture tube, is produced by coating opposite major surfaces of a thin metal sheet with etch-resistant patterns. One pattern comprises an array of larger open areas surrounded by etch-resistant material, and the other pattern comprises smaller open areas of similar shape and registered with the larger open areas.
Each of the smaller open areas has therewithin a still-smaller solid area of etch-resistant material. The coated sheet is etched from both sides to produce the desired apertures, and then the coatings are removed from the sheet.
Description
RCA 68,334 105;~673 This invention relates to a novel method for producing an apertured work piece, particularly a shadow mask for a color television picture tube.
A shadow-mask-type color television picture tube includes a color-selection electrode closely spaced from a viewing-screen structure The electrode is in the form of an apertured mask which shadows portions of the viewing screen from the electron beams during the operation of the tube. To reduce scattering of beam electrons off the sides of the shadow-mask apertures during electron-beam scanning, ; the apertures are tapered from the screen side towards the electron-beam source. For practical reasons, the narrowest part of each aperture is a "knife edge" which is located a short distance below the mask surface. This short distance is referred to as the "step height" of the knife edge.
. United States Patent Nos. 2,750,524 and 3,679,500 describe methods for producing a shadow-mask with apertures having a small step height. Both methods, however, involve two separate etching steps and two separate resist-coating steps.
In the novel method of the invention, an array of tapered apertures is produced in a metal sheet by coating the opposite major surfaces of the sheet with etch-resistant patterns, one pattern comprising larger open areas surrounded by etch-resistant material, and the other pattern comprising similarly-shaped, but smaller open areas registered with the .
larger areas. Each of the smaller open areas has therewith-in a still-smaller solid area of etch-resistant material.
; Preferably, in at least one dimension, the still-smaller
A shadow-mask-type color television picture tube includes a color-selection electrode closely spaced from a viewing-screen structure The electrode is in the form of an apertured mask which shadows portions of the viewing screen from the electron beams during the operation of the tube. To reduce scattering of beam electrons off the sides of the shadow-mask apertures during electron-beam scanning, ; the apertures are tapered from the screen side towards the electron-beam source. For practical reasons, the narrowest part of each aperture is a "knife edge" which is located a short distance below the mask surface. This short distance is referred to as the "step height" of the knife edge.
. United States Patent Nos. 2,750,524 and 3,679,500 describe methods for producing a shadow-mask with apertures having a small step height. Both methods, however, involve two separate etching steps and two separate resist-coating steps.
In the novel method of the invention, an array of tapered apertures is produced in a metal sheet by coating the opposite major surfaces of the sheet with etch-resistant patterns, one pattern comprising larger open areas surrounded by etch-resistant material, and the other pattern comprising similarly-shaped, but smaller open areas registered with the .
larger areas. Each of the smaller open areas has therewith-in a still-smaller solid area of etch-resistant material.
; Preferably, in at least one dimension, the still-smaller
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. ` RCA 68,334 lS~S'~673 solid area is at least 1.0 mil wide and at least 2.0 mils smaller than the smaller open area. Both sides of the coated sheet are etched simultaneously until the desired tapered apertures are produced therein. Then, the etching is stopped, and the etch-resistant patterns~are removed from both major surfaces By employing the still-smaller solid areas of etch-resistant material within the smaller open areas, the step height can be reduced, and the uniformity of the knife edge can be improved, relative to prior-art methods.
The openings produced by the combination of patterns permits etching to occur from both surfaces of the sheet, but aontrollably limits the etching from the surface carrying the pattern comprising the smaller open areas. The novel l 15 method requires only a single coating step and a single - etching step to achieve what is achieved in two steps with the above-cited prior-art methods.
In the drawings, FIGURE l is a plan view of a metal sheet produced according to the novel method.
FIGURES 2 through 6 are sectional views through one aperture of the metal sheet, illustrating the steps of an example of the novel method;
FIGURE 7 is a superimposed plan view of etch-resistant patterns for producing circular apertures accord1ng to an example of the invention;
FIGURE 8 is a superimposed plan view of etch-resistant patterns for producing slit apertures according to another example of the invention; and FIGURE 9 is a superimposed plan view of etch-
';
. ` RCA 68,334 lS~S'~673 solid area is at least 1.0 mil wide and at least 2.0 mils smaller than the smaller open area. Both sides of the coated sheet are etched simultaneously until the desired tapered apertures are produced therein. Then, the etching is stopped, and the etch-resistant patterns~are removed from both major surfaces By employing the still-smaller solid areas of etch-resistant material within the smaller open areas, the step height can be reduced, and the uniformity of the knife edge can be improved, relative to prior-art methods.
The openings produced by the combination of patterns permits etching to occur from both surfaces of the sheet, but aontrollably limits the etching from the surface carrying the pattern comprising the smaller open areas. The novel l 15 method requires only a single coating step and a single - etching step to achieve what is achieved in two steps with the above-cited prior-art methods.
In the drawings, FIGURE l is a plan view of a metal sheet produced according to the novel method.
FIGURES 2 through 6 are sectional views through one aperture of the metal sheet, illustrating the steps of an example of the novel method;
FIGURE 7 is a superimposed plan view of etch-resistant patterns for producing circular apertures accord1ng to an example of the invention;
FIGURE 8 is a superimposed plan view of etch-resistant patterns for producing slit apertures according to another example of the invention; and FIGURE 9 is a superimposed plan view of etch-
3 resistant patterns for producing slit apertures according RCA 68,334 105'~:~73 l to still another example of the invention.
FIGURE 1 shows a plan view of an etched apertured mask blank 21 as it emerges from an etching machine used in an example of the novel method. The mask blank 21 (which here is to be used in a color televlsion picture tube) is in a metal sheet 23 comprising a succession of such mask blanks 21a, 21 and 21b. The mask blanks 21a, 21 and 21b are etched through at the margins 25 thereof, except at convenient points (not indicated) sufficient to hold the blan~s in the sheet 23. The mask blank 21 is comprised of an apertured central portion 27, defined by the broken line 28 and a skirt or peripheral portion 29 which, although not apertured, may be etched partly through.
The apertures may be circular holes arranged in a hexagonal, diamond-shaped or other array; rectangular slits arranged in vertical rows, for example, 6-mil by 30-mil slits on 30-mil centers; or of other shapes and arrangements. Also, the widths of the apertures may be uniform or graaed across ~- the array, as is known in the art.
The mask blank 21 is etched into a regular-carbon " or low-carbon cold-rolled-steel sheet about 40 to 10 mils in thickness. The etching may also be conducted in sheets of other materlals, such as invar alloy or a copper-nickel alloy. The sheet 23 is unwound from a first roll thereof, passed through the various operations including cleaning, coating~ drying, exposing, developing, etching, washing :.:
and drying (as described below), then rewound on a second roll. Subsequently, the second roll is unwound and the mask blanks 21a, 21 and 21b are stripped or torn from the ; sheet 23. The blanks are then heat treated (annealed), ."
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RCA 68,334 105'~673 I roller leveled, formed on a press, and then blackened, as is known in the art, to produce masks suitable for assembly into a picture tube.
FIGURES 2 through 6 show a sequence of steps that may be used in making one of a hexagonal array of circular apertures in the central portion 27 of a 6-mil^thick sheet 23 of cold-rolled steel (as shown in FIGURE 1). The sheet 23 is coated on both major surfaces with suitable light-sensitive coatings 31 and 33 of etch-resistant materials, e.g., dichromate-sensitized fish glue, as shown in FIGURE 2. After the coatings have dried, the coated sheet is positioned in a chase (such as is shown in United States Patent No. 3,751,250) between two light-opaque master patterns,one master pat~ern 35 for the coating 31 on one major surface of the sheet 23, and the other master pattern 37 for the other coating 33 on the other major surface of the sheet 23, as shown in FIGURE 3. The light-opaque patterns may comprise chromium or nickel metal coated layers on the inner surfaces of glass plates 39 and 41, so that the patterns 35 and 37 are physlcally against ;`
the coatings 31 and 33 respectively. The one master pattern 35 is an annular ring of about 5 mils outside diameter and 3 mils inside diameter. The other master pattern 37 is a disc or solid circle about 16 mils in diameter. Genter lines of the two master patterns are ~-~ coincident, but may be offset from one another if desired.
As shown in FIGURE 3, the coatings 31 and 33 are next exposed to hardening radiation ~shown by the arrows above and below the glass plates 39 and 41), as from a ' '' RCA 68,334 105'~673 1 carbon-arc source, which radiation passes through the glass plates 39 and 41 to be incident on the coatings 31 and 33.
The radiation insolubilizes the coatings 31 and 33 except where the master patterns 35 and 37 shadow the coatings.
When the coatings are suitably exposed, the exposure is stopped, and the master patterns are removed.
The coatings are then developed as by flushing with water or other aqueous solvent to remove the unexposed, shadowed portions of the coatings 31 and 33. As shown in FIGURE 4, after development the sheet 23 carries, on its one major surface, an etch-resistant coating having an annular opening 43 therein and, on its other major surface, an etch-resistant coating 33 having a circular or disc-s shaped opening 45 therein.
The sheet 23 with the etch-resistant coatings thereon is now etched in a single step to produce the desired tapered aperture. FIGURES 5 and 6 show the coated ` sheet 23 at an early stage (FIGURE 5) and then at the end of etching ~FIGURE 6). The etching is conducted in the usual manner by employing a ferric chloride-hydrochloric ,~ acid liquid etchant. At the initial stage shown in FIGURE
Y, 5, the etchant dissolves a small amount of the surfaces of , the sheet 23 in the uncoated areas thereof. FIGURE 5 also shows, by dotted lines, various subsequent etching surfaces that the etchant is believed to advance to.
The use of an annular opening 43 instead of a disc-shaped opening on the one major surface severely restricts the effective etching from that surface, thereby imparting only a small step height 47, as shown in FIGURE
6. If the annular opening 43 were replaced with a disc-,.,,~
RCA 68,334 lOS'~673 shapeld opening, the step height would be substantially grc~ter. The coatings 31 and 33 on thc major surfaces of the sheet 23 are removed after the etching has been completed, whereafter the work piece is ready for further processing.
FIGURE 7 shows, in plan view and superimposed S
upon one another, the master patterns in the working plates.
The significant dimensions of the annular opening of the one master pattern 35 are the inside diameter 53; the outside diameter 55; and the width S9, which is one half the difference between the outside and inside diameters. For practical reasons, the inside diameter 53 should be about 1 to 8 mils, and the outside diameter 55 should be about 3 to 10 mils.
Preferably, the difference between the outside and inside diameters is at least 2 mils, so that the width 59 of the annulus is at least 1 mil. The significant dimension for the circular opening of the other master pattern 37 is the ; dia~eter 57 which, for practical reasons is about 12 to 20 mils.
Where the apertures are graded in size from the center to edge of the apertured portion 27, the diameters ` of the annular openings are graded. Typically, the outside diameter of the annular opening 35 may grade from about 9.5 mils at the center of the mask to about 7.5 mils at the : .~
~ edge of the apertured portion 27 of the mask. The inner ~ .
diameter of the annular opening 53 may also be graded, but the widths 59 are preferably at least 1 mil with present ` etch-resistant patterns. (As the width 59 decreases, the step height decreases to a minimum of about 1 mil and then increases.) In this example, the diameter 57 of the circular area on the reverse side is about 16 mils, but this dimension is not critical and ma~ be between about 12 and 20 mils. ~here the apertures are graded in size, the RCA 68,334 105'~673 1 larger circular areas may or may not be graded in size.A typical center-to-center aperture spacing is about 25 mils.
The novel method may be empl~yed also to produce rectangular slit apertures, as illustrated by the super-imposed master patterns shown in FIGURE 8. The one master pattern 35' ~solid lines) and the other master pattern 37' ~dotted line) are shown with rectangles having rounded corners. For one example, the outside width 65 of the one master pattern 55', is about 5 mils and the outside length is about 30 mils; the inside width 63 is about 2 mils and the inside length is about 27 mils. Tn other examples, the outside width may vary from 3 to 20 mils and the inside width 63 may vary from 1 to 10 mils. However, the difference between the outside and inside widths is , . .
` preferably at least 2 mils, so the width of the annulus h;,: 69, 61 is at least 1 mil. The other master patterns 37' may vary between 12 and 24 mils in width and between 20 and 50 mils in length; however, each of the length and width dimensions of the other master pattern 37' should be larger than the corresponding dimension of the one master pattern 35' ., , ~
j FIGURE 9 shows another application of the novel ~ method for producing an array of rectangular slits. The `. 25 slit aperture master patterns shown in FIGURE 9 differ from -~, those of FIGURE 8 in that, for the one master pattern 35"
of the former, the length of the still-smaller solid area is equal to the length of the smaller open area. For practical reasons, the annular spacing 61 of the one master pattern of FIGURE 8 may be omitted, with substantially ~' -~ RCA 68,334 . _ 105'~;73 l equivalent results to those obtained with the master pa1:terns shown. Thus, in the example of FIGURE 9, only one, i.e., the horizontal, dimension of the one master pattern requires that the still-smaller solid area be at ~; 5 least 2 mils smaller than the smaller open area.
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FIGURE 1 shows a plan view of an etched apertured mask blank 21 as it emerges from an etching machine used in an example of the novel method. The mask blank 21 (which here is to be used in a color televlsion picture tube) is in a metal sheet 23 comprising a succession of such mask blanks 21a, 21 and 21b. The mask blanks 21a, 21 and 21b are etched through at the margins 25 thereof, except at convenient points (not indicated) sufficient to hold the blan~s in the sheet 23. The mask blank 21 is comprised of an apertured central portion 27, defined by the broken line 28 and a skirt or peripheral portion 29 which, although not apertured, may be etched partly through.
The apertures may be circular holes arranged in a hexagonal, diamond-shaped or other array; rectangular slits arranged in vertical rows, for example, 6-mil by 30-mil slits on 30-mil centers; or of other shapes and arrangements. Also, the widths of the apertures may be uniform or graaed across ~- the array, as is known in the art.
The mask blank 21 is etched into a regular-carbon " or low-carbon cold-rolled-steel sheet about 40 to 10 mils in thickness. The etching may also be conducted in sheets of other materlals, such as invar alloy or a copper-nickel alloy. The sheet 23 is unwound from a first roll thereof, passed through the various operations including cleaning, coating~ drying, exposing, developing, etching, washing :.:
and drying (as described below), then rewound on a second roll. Subsequently, the second roll is unwound and the mask blanks 21a, 21 and 21b are stripped or torn from the ; sheet 23. The blanks are then heat treated (annealed), ."
~4 , , .
RCA 68,334 105'~673 I roller leveled, formed on a press, and then blackened, as is known in the art, to produce masks suitable for assembly into a picture tube.
FIGURES 2 through 6 show a sequence of steps that may be used in making one of a hexagonal array of circular apertures in the central portion 27 of a 6-mil^thick sheet 23 of cold-rolled steel (as shown in FIGURE 1). The sheet 23 is coated on both major surfaces with suitable light-sensitive coatings 31 and 33 of etch-resistant materials, e.g., dichromate-sensitized fish glue, as shown in FIGURE 2. After the coatings have dried, the coated sheet is positioned in a chase (such as is shown in United States Patent No. 3,751,250) between two light-opaque master patterns,one master pat~ern 35 for the coating 31 on one major surface of the sheet 23, and the other master pattern 37 for the other coating 33 on the other major surface of the sheet 23, as shown in FIGURE 3. The light-opaque patterns may comprise chromium or nickel metal coated layers on the inner surfaces of glass plates 39 and 41, so that the patterns 35 and 37 are physlcally against ;`
the coatings 31 and 33 respectively. The one master pattern 35 is an annular ring of about 5 mils outside diameter and 3 mils inside diameter. The other master pattern 37 is a disc or solid circle about 16 mils in diameter. Genter lines of the two master patterns are ~-~ coincident, but may be offset from one another if desired.
As shown in FIGURE 3, the coatings 31 and 33 are next exposed to hardening radiation ~shown by the arrows above and below the glass plates 39 and 41), as from a ' '' RCA 68,334 105'~673 1 carbon-arc source, which radiation passes through the glass plates 39 and 41 to be incident on the coatings 31 and 33.
The radiation insolubilizes the coatings 31 and 33 except where the master patterns 35 and 37 shadow the coatings.
When the coatings are suitably exposed, the exposure is stopped, and the master patterns are removed.
The coatings are then developed as by flushing with water or other aqueous solvent to remove the unexposed, shadowed portions of the coatings 31 and 33. As shown in FIGURE 4, after development the sheet 23 carries, on its one major surface, an etch-resistant coating having an annular opening 43 therein and, on its other major surface, an etch-resistant coating 33 having a circular or disc-s shaped opening 45 therein.
The sheet 23 with the etch-resistant coatings thereon is now etched in a single step to produce the desired tapered aperture. FIGURES 5 and 6 show the coated ` sheet 23 at an early stage (FIGURE 5) and then at the end of etching ~FIGURE 6). The etching is conducted in the usual manner by employing a ferric chloride-hydrochloric ,~ acid liquid etchant. At the initial stage shown in FIGURE
Y, 5, the etchant dissolves a small amount of the surfaces of , the sheet 23 in the uncoated areas thereof. FIGURE 5 also shows, by dotted lines, various subsequent etching surfaces that the etchant is believed to advance to.
The use of an annular opening 43 instead of a disc-shaped opening on the one major surface severely restricts the effective etching from that surface, thereby imparting only a small step height 47, as shown in FIGURE
6. If the annular opening 43 were replaced with a disc-,.,,~
RCA 68,334 lOS'~673 shapeld opening, the step height would be substantially grc~ter. The coatings 31 and 33 on thc major surfaces of the sheet 23 are removed after the etching has been completed, whereafter the work piece is ready for further processing.
FIGURE 7 shows, in plan view and superimposed S
upon one another, the master patterns in the working plates.
The significant dimensions of the annular opening of the one master pattern 35 are the inside diameter 53; the outside diameter 55; and the width S9, which is one half the difference between the outside and inside diameters. For practical reasons, the inside diameter 53 should be about 1 to 8 mils, and the outside diameter 55 should be about 3 to 10 mils.
Preferably, the difference between the outside and inside diameters is at least 2 mils, so that the width 59 of the annulus is at least 1 mil. The significant dimension for the circular opening of the other master pattern 37 is the ; dia~eter 57 which, for practical reasons is about 12 to 20 mils.
Where the apertures are graded in size from the center to edge of the apertured portion 27, the diameters ` of the annular openings are graded. Typically, the outside diameter of the annular opening 35 may grade from about 9.5 mils at the center of the mask to about 7.5 mils at the : .~
~ edge of the apertured portion 27 of the mask. The inner ~ .
diameter of the annular opening 53 may also be graded, but the widths 59 are preferably at least 1 mil with present ` etch-resistant patterns. (As the width 59 decreases, the step height decreases to a minimum of about 1 mil and then increases.) In this example, the diameter 57 of the circular area on the reverse side is about 16 mils, but this dimension is not critical and ma~ be between about 12 and 20 mils. ~here the apertures are graded in size, the RCA 68,334 105'~673 1 larger circular areas may or may not be graded in size.A typical center-to-center aperture spacing is about 25 mils.
The novel method may be empl~yed also to produce rectangular slit apertures, as illustrated by the super-imposed master patterns shown in FIGURE 8. The one master pattern 35' ~solid lines) and the other master pattern 37' ~dotted line) are shown with rectangles having rounded corners. For one example, the outside width 65 of the one master pattern 55', is about 5 mils and the outside length is about 30 mils; the inside width 63 is about 2 mils and the inside length is about 27 mils. Tn other examples, the outside width may vary from 3 to 20 mils and the inside width 63 may vary from 1 to 10 mils. However, the difference between the outside and inside widths is , . .
` preferably at least 2 mils, so the width of the annulus h;,: 69, 61 is at least 1 mil. The other master patterns 37' may vary between 12 and 24 mils in width and between 20 and 50 mils in length; however, each of the length and width dimensions of the other master pattern 37' should be larger than the corresponding dimension of the one master pattern 35' ., , ~
j FIGURE 9 shows another application of the novel ~ method for producing an array of rectangular slits. The `. 25 slit aperture master patterns shown in FIGURE 9 differ from -~, those of FIGURE 8 in that, for the one master pattern 35"
of the former, the length of the still-smaller solid area is equal to the length of the smaller open area. For practical reasons, the annular spacing 61 of the one master pattern of FIGURE 8 may be omitted, with substantially ~' -~ RCA 68,334 . _ 105'~;73 l equivalent results to those obtained with the master pa1:terns shown. Thus, in the example of FIGURE 9, only one, i.e., the horizontal, dimension of the one master pattern requires that the still-smaller solid area be at ~; 5 least 2 mils smaller than the smaller open area.
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Claims (6)
1. A method for producing an apertured work piece comprising a thin metal sheet having an array of tapered apertures therethrough, comprising the steps of:
a. simultaneously coating opposite major surfaces of said sheet with etch-resistant patterns corresponding to said array, the pattern on one of said surfaces comprising larger open areas surrounded by etch-resistant material, and the pattern on the opposite one of said surfaces comprising smaller open areas, each of said smaller open areas having therewithin a still-smaller solid area of etch-resistant material;
b. simultaneously etching both sides of said coated sheet until said tapered apertures are produced therethrough;
c. stopping said etching; and d. removing said etch-resistant patterns from both said surfaces of said sheet.
a. simultaneously coating opposite major surfaces of said sheet with etch-resistant patterns corresponding to said array, the pattern on one of said surfaces comprising larger open areas surrounded by etch-resistant material, and the pattern on the opposite one of said surfaces comprising smaller open areas, each of said smaller open areas having therewithin a still-smaller solid area of etch-resistant material;
b. simultaneously etching both sides of said coated sheet until said tapered apertures are produced therethrough;
c. stopping said etching; and d. removing said etch-resistant patterns from both said surfaces of said sheet.
2. The method defined in claim 1, wherein, in at least one dimension, said still-smaller solid area is at least 1 mil wide and at least 2 mils smaller than the corresponding smaller open area.
3. The method defined in claim 2, wherein in said one dimension, said still-smaller solid area is about 2 to 3 mils wide and said corresponding smaller open area is about 6 to 10 mils wide.
4. The method defined in claim 1, wherein said larger open areas are substantially circular areas about 12 to 20 mils in diameter and said smaller open areas are substantially circular areas about 6 to 10 mils in diameter.
5. The method defined in claim 1, wherein said larger open areas are substantially rectangular areas about 12 to 20 mils wide and said smaller open areas are substantially rectangular areas about 4 to 10 mils wide.
6. The method defined in claim 5, wherein the length of said still-smaller solid area is equal to the length of the corresponding smaller open area.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US489393A US3929532A (en) | 1974-07-17 | 1974-07-17 | Method for etching apertured work piece |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1052673A true CA1052673A (en) | 1979-04-17 |
Family
ID=23943671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA231,291A Expired CA1052673A (en) | 1974-07-17 | 1975-07-11 | Method for producing an apertured work piece |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US3929532A (en) |
| JP (1) | JPS5134835A (en) |
| BE (1) | BE831391A (en) |
| CA (1) | CA1052673A (en) |
| DE (1) | DE2532048A1 (en) |
| FR (1) | FR2278795A1 (en) |
| GB (1) | GB1512825A (en) |
| IT (1) | IT1039337B (en) |
| NL (1) | NL7508514A (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4105493A (en) * | 1975-07-05 | 1978-08-08 | The Gillette Company | Production of shaving foil |
| US4094678A (en) * | 1976-12-07 | 1978-06-13 | Zenith Radio Corporation | Method of making curved color cathode ray tube shadow masks having interregistrable electron beam-passing aperture patterns |
| US4061529A (en) * | 1977-02-28 | 1977-12-06 | Rca Corporation | Method for making etch-resistant stencil with dichromate-sensitized casein coating |
| JPS607343B2 (en) * | 1978-10-18 | 1985-02-23 | 日新製鋼株式会社 | Manufacturing method of shadow mask for color television cathode ray tube |
| JPS5579025A (en) * | 1978-12-09 | 1980-06-14 | Higashine Shigai Nishi Itsuchiyou Kyoritsu Eisei Shiyori Kumiai | Exhaust gas deodorizing apparatus for excretion tank truck |
| US4303466A (en) * | 1980-06-19 | 1981-12-01 | Buckbee-Mears Company | Process of forming graded aperture masks |
| JPS5748491Y2 (en) * | 1980-11-13 | 1982-10-25 | ||
| CA1204143A (en) * | 1982-08-27 | 1986-05-06 | Kanemitsu Sato | Textured shadow mask |
| US4632726A (en) * | 1984-07-13 | 1986-12-30 | Bmc Industries, Inc. | Multi-graded aperture mask method |
| US5348825A (en) * | 1991-07-02 | 1994-09-20 | Dai Nippon Printing Co., Ltd. | Method for manufacturing shadow mask and shadow mask manufactured by said method |
| JP3282347B2 (en) * | 1993-09-07 | 2002-05-13 | ソニー株式会社 | Etching method, color selection mechanism and manufacturing method thereof, and cathode ray tube |
| JP2764526B2 (en) * | 1993-09-28 | 1998-06-11 | 大日本印刷株式会社 | Manufacturing method of aperture grill and aperture grill |
| JPH07320652A (en) * | 1994-05-27 | 1995-12-08 | Toshiba Corp | Manufacture of color picture tube and shadow mask |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2437228A (en) * | 1943-08-05 | 1948-03-02 | Buckbee Mears Co | Reticle |
| US2750524A (en) * | 1951-11-15 | 1956-06-12 | Mergenthaler Linotype Gmbh | Perforate mask for multicolor television apparatus and method of producting same |
| US3329541A (en) * | 1960-05-20 | 1967-07-04 | Buckbee Mears Co | Method of forming fine mesh screens |
| US3609033A (en) * | 1969-08-15 | 1971-09-28 | Buckbee Mears Co | Mask for etching enlargement |
| US3679500A (en) * | 1970-08-07 | 1972-07-25 | Dainippon Screen Mfg | Method for forming perforations in metal sheets by etching |
-
1974
- 1974-07-17 US US489393A patent/US3929532A/en not_active Expired - Lifetime
-
1975
- 1975-06-23 IT IT24681/75A patent/IT1039337B/en active
- 1975-07-01 GB GB27703/75A patent/GB1512825A/en not_active Expired
- 1975-07-11 FR FR7521854A patent/FR2278795A1/en active Granted
- 1975-07-11 CA CA231,291A patent/CA1052673A/en not_active Expired
- 1975-07-15 JP JP50087168A patent/JPS5134835A/en active Granted
- 1975-07-15 BE BE158319A patent/BE831391A/en unknown
- 1975-07-16 NL NL7508514A patent/NL7508514A/en not_active Application Discontinuation
- 1975-07-17 DE DE19752532048 patent/DE2532048A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| AU8271875A (en) | 1977-01-06 |
| JPS5134835A (en) | 1976-03-24 |
| FR2278795A1 (en) | 1976-02-13 |
| GB1512825A (en) | 1978-06-01 |
| IT1039337B (en) | 1979-12-10 |
| DE2532048A1 (en) | 1976-02-05 |
| FR2278795B1 (en) | 1979-08-24 |
| NL7508514A (en) | 1976-01-20 |
| JPS5416457B2 (en) | 1979-06-22 |
| US3929532A (en) | 1975-12-30 |
| BE831391A (en) | 1975-11-03 |
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